This invention relates to a lift gate, for attachment to a cargo vehicle such as a truck or trailer, particularly to the rear loading end of such truck or trailer. More particularly, this invention relates to such lift gate which includes a generally horizontal load platform which is rotated upward to a vertical storage position.
One object of this invention is to provide a lift gate wherein the load platform is designed for ramping with the ground surface or a dock surface to facilitate the loading of cargo with small wheeled dollies and trucks.
Another object of this invention is to provide a lift gate wherein the load platform is moveable between a lower slightly downwardly inclined ground ramping position and a horizontal bed position aligned with the cargo bed of the vehicle.
A further object of this invention is to provide a lift gate wherein the load platform is generally wedge shaped in longitudinal cross section, providing a planar load surface and a thin trailing edge to facilitate ramping with a ground surface or a dock surface.
Still another object of this invention is to provide a lift gate wherein the load platform in its bed position is releaseable from its horizontally supported position to enable it to swing downwardly as well as upwardly from the vehicle bed to function in a dock ramping plate.
A still further object of this invention is to provide a lift gate wherein the load platform is swingable from its horizontal bed position to a vertical storage position through further raising of the lift arms.
Another object of this invention is to provide a lift gate wherein the load platform is supported in a vertical storage position behind the cargo body, and wherein the platform automatically assumes a horizontal bed position aligned with the vehicle cargo bed when swung from the vertical storage position.
A further object of this invention is to provide a lift gate wherein the load platform swings about a common pivot axis to accommodate upward and downward movement of the platform for ramping with a dock surface, and the accommodate movement of the platform between the horizontal bed position and the vertical storage position.
Still another object of this invention is to provide a lift gate including a control mechanism for the platform which latches to the rearward end of the cargo bed, and which provides a horizontal pivot axis for the platform enabling ramping functions of the platform and enabling swinging of the platform to the vertical storage position.
A still further object of this invention is to provide a lift gate including a control mechanism associated with a load platform, which control mechanism together with lift arms enable movement of the platform from an inclined ground ramping position to a horizontal bed position.
These objects are accomplished in a lift gate for attachment to a vehicle having a cargo bed, which lift gate includes a load platform having a leading edge and a trailing edge. An attitude control mechanism for the platform includes a pair of platform uprights which are disposed at opposite sides of the platform adjacent to its leading edge, and a pair of upper and lower arms pivotally connected to each of the platform uprights and to the vehicle, for controlling the attitude of the platform during the raising and lowering thereof between ground and bed positions. A pair of lift arms are oscillatable about a horizontal axis between lower and upper positions. Longitudinally moveable pivot means are mounted on the platform, and the distal ends of the lift arms are pivotally connected to those moveable pivot means. Power means affects the raising of the lift arms from the lower position.
More particularly, the platform is pivotally connected at its leading edge to the lower ends of the platform uprights. Platform support arms are pivotally mounted at opposite sides of the platform rearward from the platform uprights. These arms have catch members at their distal ends and the platform uprights have coacting catch members at their upper ends, which catch members are engageable to support the platform in load carrying attitude relative to the platform uprights.
Still more particularly a latch mechanism latches the attitude control mechanism to the rearward end of the cargo bed, to fix the load platform pivot axis relative to the cargo bed.
The novel features and the advantages of the invention as well as additional objects thereof, will be understood more fully from the following description when read in connection with the accompanying drawings.